Illuminant for electrical incandescent lamps.



0. M. THOWLESS.

ILLUMINANT FOR ELECTRICAL INOANDBSGENT LAMPS.

APPLIUATION FILED NOV.20.1908.'

1,023,485. Patented Apr. 16, 1912 I wuc Hot ORLANDO m. THOWLESS, or NEwAnK, NEW .r'nnsnr.

ILLUMIN AN '1' FOR ELECTRICAL INCANDESCENT LAMPS.

Specification of {otters Patent.

Patented Apr. 16, 1912.

Application filed November 20, 1908. Serial No. 488,629.

To all whom it may concern:

Be it known that I, Onnanno M. Trrow- Less, a subject of th King of Great Britain, residing at Newark, in the county of and State of New Jersey, have invented new and useful Improvements in Illuminants for Electrical Incandescent Lamps, of which the following is a specification.

My invention relates to a new and improved illuminant for electrical incandescent lam )S.

T 1e object of my invention is to provide an electrical incandescent lamp with an illuminant having the quality of lighting up quickly when a proper current of electricity is connected therewith and contemplates the production of an illuminant formed of a body which is normally non-colnluctivc but capable of becoming a good conductor when heated having closely attached to it a permanent normally conductive material capable of raising the attached body to a conductive and light-giving temperature. To attain this object I form a refractory rod of the shape and size required and on this rod, which may be either solid or hollow, I cause to be formed a coating of some refractory conducting material which has no decomposing etlect when the rod is in operation. The rod is connected with terminals for conducting current either before or after receiving the coating and then placed in a proper receptacle to form an acceptable lamp. In case the coating should be one that would be destroyed in the air, such as tungsten, molybdenum, &c., it will be necessary for the receptacle (a lamp-bulb for instance) to be exhausted of air in the wellknown way, and in some cases have indifferent gas therein.

One method of making my illuminant is to form a rod of a mixturc of powdered refractory metallic oxids or a mixture of such with a small amount of flux, and, after forming the mixture into the required shape, subject it to a very high temperature, such as the elcctric arc or the oxyhydrogcn flame, until it has a vitrified appearance. This will produce. a rod which is normally a nonconductor of electricity, but which becomes a conductor when heated. It may then be mounted and receive the coating of conducting material. The coating may be done by placing the rod in a bell-jar, connecting it with a suitable source of electricity, heating it by means of a flame which causes it to glow, and, after the air has been exhausted -from the bell-jar, allow vapors of suitable halogen salts to be admitted in connection with hydrogen or other suitable reducing gas, thereby coating the heated rod with the conductive material contained in the vapors and gases. In some cases this coating may be carbid of boron, nitrid of boron, carbid of silicon, or other cal-bids or nitrids.

In some cases the rod may be coated by transferring a coating from a filament or rod which has already been subjected to a treating or flashing process. For instance, if carbid of boron or' carbid of silicon be deposited, by flashing on a base such as an electricarc pencil or even on an electrical incandescent filament, and this be placed in a flaslr ing jar or in a lamp-bulb in close proximity to an oxid rod such as mentioned, and this rod not heated, a current being caused to traverse the flashed pencil or filament, as the case may be, raising it to a rather high tcmperature in an exhausted chamber, the coating of cal-bid of boron or silicon will be deconn'iosed and a deposit essentially of boron or silicon or both, if both carbids are present, will lie formed upon the cold rod, and this coating may be used for the purpose of heating up the rod when it is placed in proper position in the lamp.

In all cases the coating must be sufliciently refractory to withstand the incandescent heat without. being dissipated, and it is better to have the terminals connected with the rod before the coating is applied, so that a better conductive connection may result. Cement, however, may be used and in some cases a mechanical or welded joint may be desirable.

The coating has so far been described as a deposit on the outside of the rod, but in some cases it may be desirable to have the deposit on the inside of a hollow rod, in which case the methods pursued would be somewhat modified.

In the first method mentioned it would be necessary to have the hollow rod serve as the flashing-jar and the vapors should be caused to pass through the hollow rod while the rod is in a heated state, which will cause a deposition on the inner walls.

In the other method given it would be necessary to place a fine filament, which had already been flashed with some conductive substance, as before set forth, through the tube, and heat this filament to a high temperature, keeping the hollow red as cool as possible and free from any electrical connection; it would be found that the flashed material would be decomposed and the proper conductive material e osited on the inner walls of the hollow IOt In all cases where a substance is used for the coating that would be quickly destroyed by heat in air, it will be necessary to place the completed illuminant in an exhausted globe or one containing indifierent gas, and even in some cases where the 0 en air would not be destructive to the coating it may be found better to place the illuminant in an exhausted bulb or one containing inert gas, as the economy of such would be higher. However, in such cases a very small amount of oxygen gas may be beneficial.

It may be proper to use a resistance wire in connection with the illuminant. This may be attached by one end of the leading-in wires and the other end of the wire to the illuminant-connecting wire. The wire may be of latinum, nickel, iron or of any other suitab e metal possessing the proper characteristics. It may be wound around the stem of the lamp inside the bulb, and the stem may be corrugated to hold the wire in place.

In some forms of this illuminant it may be desirable to only coat a part of the rod, and this may be accom )lished by stopping oil that part of the rod on which no deposit is required. This may be done by any suitable means, such as an oxid form having a recess into which the rod may be placed, leaving a part of the rod exposed to receive the coating. After the deposit has'been made the form may be removed, and the coatin will be made only on the part required: which, of course, should be continuous from one connection to the other.

In some cases it may be advantageous to deposit a second coating to protect the first or a protective coating may be used upon the rod to prevent a decomposition which might occur with some materials used as a coating directly on the rod.

In the accompanying drawin s Figure 1 is a view of an electirc lamp em odying my invention. Fig. 2 is an enlarged front view of rod having the coating thereon, with connecting wires attached. Fig. 3 is a cross-section of Fig. 2. Fig. 4 is a cross-section of a hollow rod, showing the inside coating.

Fig. 5 shows the partial coating. Fig. 6 is a sectional view of Fig. 5, taken on the line X, X.

Similar letters refer to similar parts in allthe views in which A is the lamp-bulb; B, the corrugated extended glass stem around which the resistance wire may be wrappml; (3 shows the cement or joint connecting the wires and the glower; I), represents the completed glower; E, is the coating on the outside of the rod; F, is the coating on the inside of the tubular rod in Fig. 4.; (la-G, are the supports for the glou'cr, and serve as connecting wires; H, is the resistance wire; J, represents the rod generally; K, is the partial coating.

Having thus described my invention, what I claim is:

1. An illuminant for electrical incandescent lamps consisting of a refractory vitrified glower combined with a heating body composed essentially of refractory nonmctallic conductive material.

2. An illuminant for electrical incandesccnt lamps consisting of a refractory vitriticd body having a portion of the same coat.- ed with refractory non-metallic conductive nmterial.

it. A heating body for electriml incandescent lamps composed csscntially of refractory carbid.

4. A heating body for electrical incandescent lamps composed essentially of a carbid of silicon.

5. heating body for electrical incandescent lamps composed essentially of nonmctallic conductive substance.

in testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses.

ORLANDO M. THOWLESS.

\Vi t nesscs:

Ilniuunrr L. 'lnownass, An'rnun J. Tnownnss. 

